Are not all/most organisms built to protect reproductive organs?
Not just "male organisms are built to be protective of their testicles"?
Please explain what you mean by: "that one, centralized vulnerability is why a kick in the testicles hurts more than being hit on the head."
A kick in the head can leave you as unable to reproduce as a kick in the balls. I think it is more likely to kill you, too.
Are not all/most organisms built to protect reproductive organs? Not just "male organisms are built to be protective of their testicles"?
Please explain what you mean by: "that one, centralized vulnerability is why a kick in the testicles hurts more than being hit on the head." A kick in the head can leave you as unable to reproduce as a kick in the balls. I think it is more likely to kill you, too.